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Subject: Re: [boost] Boost.Test updates in trunk: need for (mini) review?
From: Ian Emmons (iemmons_at_[hidden])
Date: 2012-10-26 08:41:50

On Oct 19, 2012, at 11:03 PM, Gennadiy Rozenal wrote:
> It's been a long while since I merged any changes into boost release and by
> now there are whole bunch of new features there. Some are small, but some
> others are big ones such that they can change the way people use the library.
> I'd like to list them here (excluding bug fixes and removal of deprecated
> interfaces) and ask what should we do with these. Specifically let me know
> if you think these require some kind of (mini) review from community, but any
> other comments are welcome as well.

Excellent stuff! Thanks for this work. I have a couple of comments.

First, __please__ pay attention to documentation. I know you have said that documentation isn't something you like/want to do, but a library without good documentation is useful only to the writer. In other words, it is (in a general purpose case like this) simply a waste of time.

Second, I have below suggested some terminology changes. (Not for BOOST_CHECKA -- you have plenty of input on that.) Some believe that a name is only a name, but I disagree. Choosing names carefully is, in my opinion, a powerful means of communication and documentation.

> II. New "data driven test case" subsystem
> <<snip>>
> d) join - dataset constructed by joining 2 datasets of the same type
> int a[] = {1,2,3};
> int b[] = {7,8,9};
> data::make(a) + data::make(b) - dataset with 6 integer values

This should be called "concatenation", not "joining". People with a database background will expect something called "join" to increase the arity of the result.

> e) zip - dataset constructed by zipping 2 datasets of the same size, but not
> necessarily the same type
> This dataset has an arity which is sum of argument dataset arities.
> int a[] = {1,2,3};
> char* b[] = {"qwe", "asd", "zxc"};
> data::make(a) ^ data::make(b)
> dataset with 3 samples which are pairs of int and char*.

Calling this "zipping" is odd (at least to me). Makes it sound like a compression facility. Perhaps "tupling" would be better.

I also think the choice of operator here is not ideal. How does the xor operator evoke any notion of this operation? I would choose bitwise-or "|" because that is sometimes used as a flat-file column delimiter. (Actually, my favorite choice would be the comma operator to go along with the "tupling" terminology, but who am I to defy Scott Meyers' More Effective C++, Item 7?)

> f) grid - dataset constructed by "multiplying" 2 datasets of the same different
> sizes and types type
> This dataset has an arity which is sum of argument dataset arities.
> int a[] = {1,2,3};
> char* b[] = {"qwe", "asd"};
> double c[] = {1.1, 2.2};
> data::make(a) * data::make(b) * data::make(c)
> dataset with 12 samples which are tuples of int and char* and double.

For people with a database background, "cross product" is the obvious name for this. Calling it anything else is silly. Also, I think you mean that the arity is the *product* of the argument dataset arities.


Ian Emmons

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